EPUB3 Studio
EPUB3 Studio
EPUB 3 Editor & Validator
EPUB3 Studio is a powerful, offline-first digital publication authoring and validation studio engineered specifically for macOS. Inspect, edit, and validate reflowable and fixed-layout EPUB 3 publications with realistic book spread previews, code split-views, and European Accessibility Act (EAA) compliance diagnostics.
✨ Core Features
2-Page Spread & Multi-Device Emulation
Preview book spreads with true two-page multi-column reflow, center spine creases, and customizable device viewports for Apple iPad / Books, Kindle Paperwhite, Kobo, and iPhone.
Visual, Code & Split-View Editing
Edit XHTML chapters, CSS stylesheets, and package manifests side-by-side with instant live updates. Full syntax highlighting and error detection built-in.
Offline Pre-Flight Diagnostics & Auto-Fix
Validate your EPUB against IDPF and W3C specifications. Identify missing manifest items, orphan media files, broken references, and auto-repair package tags with a single click.
European Accessibility Act (EAA) & WCAG
Audit and enforce digital accessibility standards. Verify image alternative text, reading hierarchies, language metadata, and mandatory WCAG 2.2 schema tags.
Visual OPF Metadata & Cover Manager
Manage publication metadata, ISBNs, authors, languages, and cover artwork through a native macOS form interface without hand-editing raw XML.
100% Offline & Private
Zero telemetry, no user tracking, and no external server dependencies. All book content and processing remain strictly on your Mac.
⚙️ Technical Specifications
- Operating System: macOS Monterey 12.0 or later (fully compatible with macOS Ventura, Sonoma, and Sequoia)
- Hardware Architecture: Universal 2 Binary (Native Apple Silicon M1/M2/M3/M4 & Intel x86_64)
- Supported Formats: EPUB 3.3, EPUB 3.0.1, XHTML5, CSS3, SVG, MathML, NCX (legacy fallback)
- Security: macOS App Sandboxed with explicit read/write file access permissions
💬 App Support & Inquiries
Need help with EPUB3 Studio?
We are dedicated to providing authors, publishers, and developers with a seamless experience. If you encounter any bugs, have questions regarding EPUB validation, or wish to suggest new features, our support team is here to assist you.
Direct Support Contact:
📧 Email: support@sukheshcs.com
⏱️ Response Time: Usually within 24 to 48 hours.
Frequently Asked Questions
How do I open an existing EPUB file?
Use the top toolbar “Open EPUB” button or drag and drop any valid .epub file into the window.
Does EPUB3 Studio modify my original files automatically?
No. EPUB3 Studio works with your publication in an isolated workspace and only writes changes when you click Save or Export EPUB.
Is an internet connection required?
No. EPUB3 Studio is 100% offline. All editing, rendering, and pre-flight validation take place locally on your computer.
🛡️ Privacy Policy Strict Privacy
Last Updated: October 2026
At EPUB3 Studio, your privacy and intellectual property are our highest priorities. This Privacy Policy details our practices concerning information collection, data storage, and user privacy:
1. Zero Personal Data Collection
EPUB3 Studio does not collect, harvest, store, transmit, or share any personal identifying information, browsing habits, IP addresses, or device identifiers. There are no tracking scripts, analytics SDKs, advertising frameworks, or cookies embedded within the application.
2. Local File Processing & Content Security
All digital book files (.epub), XHTML documents, stylesheets, cover art, and media you open or create in EPUB3 Studio are processed exclusively on your local device. No publication content is ever transmitted over the network or uploaded to external servers.
3. macOS App Sandbox Compliance
The application runs in accordance with Apple’s macOS App Sandbox security guidelines. EPUB3 Studio only accesses files and directories that you explicitly grant access to via standard open and save dialogs.
4. Privacy Policy Inquiries
If you have questions regarding our privacy commitments or data handling policies, please contact us at:
📧 Email: support@sukheshcs.com